Food industry wastes clarification esp. for olive oil prodn. - comprises two aeration stages with dilution by recycled activated sludge water

摘要

In a biological clarification system, the wastes from the food industry pass from a storage tank to a first activation stage where they are diluted at a rate of 1:50 to 1:400 with a water containing activated sludge. After intermittent aeration at a space loading of 1-8 kg BOD/m3.d another dilution at the same rate follows in a second activation stage. Sepn. from the activated sludge in a settling basin is followed by denitrification and final clarification. After aeration, a constant quantity of activated sludge is recycled. Used for clarification of effluents from prodn. of olive oil by pressing olive fruit. No make-up clean water is needed for the dilution and recycled water from the aeration tanks has proved very satisfactory. This system results in very highly loaded plants with excellent economy in operation. The BOD in the outgoing fluid is kept below 25 mg/l and COD under 150 mg/l.